The present invention generally relates to a cleaning apparatus and to a method of cleaning and, more particularly, to vacuum-type cleaners which apply a cleaning fluid containing a liquid component and a detergent component onto the object to be cleaned and subsequently which remove the cleaning fluid together with the entrained contaminants.
Cleaning apparatus are known for cleaning furniture, rugs and analogous textile material objects. Such an apparatus includes a cleaning head having an intake opening which is in communication with a suction channel and which is adapted to be juxtaposed with a contaminant-bearing object to be cleaned, and also includes nozzles which spray a pressurized stream of cleaning fluid directly onto the object. However such apparatus have the disadvantage that the pressurized stream is directed normally through the plane of the intake opening so that the stream actually tends to force the contaminant dirt particles contained in the upper regions of the object even further deeper into the interstices of the base web. The dirt particles thereby tend to become anchored and accumulate in the fabric material, thus making subsequent cleaning operations necessary. Such additional cleaning operations are disadvantageous because they are costly and increase the wear of the fabric by exposing the fabric for longer periods of time to large suction forces which are now required to remove the more deeply embedded dirt and by exposing the fabric to the chemical action of the chemical detergent agents.
The prior art also has the disadvantage that the cleaning liquid is applied to an object to be cleaned at points, or in strips when the cleaning head is moving along the objects, i.e. it is applied non-uniformly. In order to achieve uniform wet cleaning over the whole surface of the objects the cleaning head has to be moved several times over the same area of the object.
The prior art also has the disadvantage that when the cleaning head is to be lifted from a respective contaminated portion of an object or when the cleaning head is applied only partially to an object, the cleaning fluid tends to drip down onto the object through the intake opening. This problem is evidently disadvantageous and has been solved only in the unsatisfactory manner of requiring an operator to repeatedly turn off the supply of cleaning fluid prior to lifting the cleaning head to another location.
Another cleaning head for cleaning surfaces of carpets includes a suction cap connected to a generator of vacuum and also includes a series of nozzles, the outlets of which are of small area and are directed directly on to the surface of the carpet or on to the plane of application of the cleaning head formed by the rim of the suction cap. The nozzles are connected via a supply duct to an aerated fluid reservoir, so that cleaning fluid leaves the outlets only if it is drawn out of them by the sub-pressure that becomes established in the suction cap. In this way, upon partial application of the cleaning head or with the cleaning head lifted from the carpet loss or dripping of cleaning fluid is avoided. However, disadvantages are that the quantity of fluid that can be emitted by the nozzles per unit of time and hence the depth of penetration of the cleaning fluid into the carpet is limited, and it is practically impossible to work with the cleaning head above the level of fluid in the fluid reservoir, as for example when cleaning curtains, wall coverings or the like. The range of use of the cleaning head is therefore restricted as regards the materials to be cleaned, and the cleaning effect is also limited. The cleaning of an object is strictly limited to the upper surface regions. Deeply embedded dirt cannot be effectively picked up.